The present invention relates to methods and apparatus for producing phase change ice particulate saline slurries of very high fluidity, cooling capacity and stability.
Phase change slurries in the form of high concentrations of small ice particles in a liquid carrier have dramatically increased coolant capacity as compared to other liquids such as single phase water or other liquids involving no heat of fusion effects. Phase change ice slurries developed by the present inventor Kenneth E. Kasza have been used for cooling in large building complexes. The development of ice slurries by the inventor for cooling buildings has shown that ice particles suspended in water or other carrier liquid, if engineered to have the correct characteristics, can be pumped as readily as water and are stable for significant periods of time without agglomeration where ice particles freeze together or entangle in clusters. The cooling capacity of such a slurry can be 5 to 10 times, depending on the particular loading in the carrier liquid, that of an equal amount of water which exhibits only sensible heat cooling capacity. For use in cooling buildings, the particles preferably are small relative to the conduit diameter, not loaded to a level of more than 30% ice in order to enhance delivery to the target cooling zone, and relatively smooth to avoid particle entanglement and formation of large clusters. Small additions of certain types of chemicals, such as freezing point depressants, when added to a slurry during an appropriate time when making the slurry, have been shown to dramatically improve the fluidity and storability of the slurry by altering the microscale features (smoothing) of the individual particles comprising the slurry.
A need exists for an improved method and apparatus for producing phase change particulate saline slurries. It is desirable to produce phase change particulate saline slurries, with high cooling capacity, fluidity, and storability, for example for use to induce targeted protective hypothermia of human organs/tissue during medical treatment.
It is an object of the present invention to provide methods and apparatus for producing phase change particulate saline slurries.
It is an object of the present invention to provide an improved phase change particulate saline slurry.
In brief, a phase change particulate saline slurry and methods and apparatus are provided for producing phase change particulate saline slurries. One method for producing phase change particulate saline slurries includes the steps of providing a liquid with a set percentage freezing point depressant to form a first solution, such as, a set percentage saline solution; cooling the first solution to a set temperature to produce ice particles; and increasing an ice particle concentration under controlled temperature for a period of time to provide a set ice particle concentration for the phase change particulate saline slurry.
In another method for producing phase change particulate saline slurries, water and a first set amount of sodium chloride are provided to produce a saline solution. The saline solution is cooled to a set temperature. A selected percentage of chunk ice is added to the saline solution and the chunk ice is broken into ice particles. The ice particles have a small size. Next a second set amount of sodium chloride is added and distributed for smoothing of the ice particles.
A phase change particulate saline slurry includes a water and sodium chloride solution. The sodium chloride is provided in a range between about 0.5% to 6.0%. A percentage of ice particles is provided in the range between about 5% to 50%. The ice particles have a size of about 1 mm or less than 1 mm; and the ice particles have a generally smooth shape.
In accordance with features of the invention, the total saline solution concentrations resulting from the total of the first set amount and the second set amount of added sodium chloride are preferably in the range of about 0.5% to 6.0%. The loadings or percentage of ice particles are preferably in the range of 5% to 50%. The resulting slurry if to be stored for later use is stored in a highly insulated container to reduce melt out of ice particles and temperature gradient in the stored slurry which can cause ice particle freezing together and reduce fluidity.